sfl::static_flat_set

Table of Contents

Summary
Template Parameters
Public Member Types
Public Data Members
- static_capacity
Public Member Functions
- (constructor)
- (destructor)
- operator=
- key_comp
- value_comp
- begin, cbegin
- end, cend
- rbegin, crbegin
- rend, crend
- nth
- index_of
- empty
- full
- size
- max_size
- capacity
- available
- clear
- emplace
- emplace_hint
- insert
- insert_range
- erase
- swap
- lower_bound
- upper_bound
- equal_range
- find
- count
- contains
- data
Non-member Functions
- operator==
- operator!=
- operator<
- operator>
- operator<=
- operator>=
- swap
- erase_if

Summary

Defined in header sfl/static_flat_set.hpp:

namespace sfl
{
    template < typename Key,
               std::size_t N,
               typename Compare = std::less<Key> >
    class static_flat_set;
}

sfl::static_flat_set is an associative container that contains sorted set of unique objects of type Key. Sorting is done using the key comparison function Compare.

Underlying storage is implemented as sorted vector.

Complexity of search operation is O(log N). Complexity of insert and remove operations is O(N).

This internally holds statically allocated array of size N and stores elements into this array, which avoids dynamic memory allocation and deallocation. This container never uses dynamic memory management. The number of elements in this container cannot be greater than N. Attempting to insert more than N elements into this container results in undefined behavior.

Elements of this container are always stored contiguously in the memory.

Iterators to elements are random access iterators and they meet the requirements of LegacyRandomAccessIterator.

sfl::static_flat_set meets the requirements of Container, ReversibleContainer, ContiguousContainer and AssociativeContainer.

This container is convenient for bare-metal embedded software development.

Template Parameters

```
typename Key
```
Key type.
```
std::size_t N
```
Size of the internal statically allocated array, i.e. the maximal number of elements that this container can contain.
```
typename Compare
```
Ordering function for keys.

Public Member Types

Member Type	Definition
`key_type`	`Key`
`value_type`	`Key`
`size_type`	`std::size_t`
`difference_type`	`std::ptrdiff_t`
`key_compare`	`Compare`
`value_compare`	`Compare`
`reference`	`value_type&`
`const_reference`	`const value_type&`
`pointer`	`value_type*`
`const_pointer`	`const value_type*`
`iterator`	LegacyRandomAccessIterator and LegacyContiguousIterator to `const value_type`
`const_iterator`	LegacyRandomAccessIterator and LegacyContiguousIterator to `const value_type`
`reverse_iterator`	`std::reverse_iterator<iterator>`
`const_reverse_iterator`	`std::reverse_iterator<const_iterator>`

Public Data Members

static_capacity

static constexpr size_type static_capacity = N;

Public Member Functions

(constructor)

static_flat_set() noexcept(std::is_nothrow_default_constructible<Compare>::value)

explicit static_flat_set(const Compare& comp) noexcept(std::is_nothrow_copy_constructible<Compare>::value)

Effects: Constructs an empty container.

Complexity: Constant.

template <typename InputIt>
static_flat_set(InputIt first, InputIt last);

```
template <typename InputIt>
static_flat_set(InputIt first, InputIt last, const Compare& comp);
```
Preconditions: std::distance(first, last) <= capacity()

Effects: Constructs the container with the contents of the range [first, last).

If multiple elements in the range have keys that compare equivalent, then the first element is inserted.

Note: These overloads participate in overload resolution only if InputIt satisfies requirements of LegacyInputIterator.

Complexity: Linear in std::distance(first, last).

static_flat_set(std::initializer_list<value_type> ilist);

```
static_flat_set(std::initializer_list<value_type> ilist, const Compare& comp);
```
Preconditions: ilist.size() <= capacity()

Effects: Constructs the container with the contents of the initializer list ilist.

If multiple elements in the range have keys that compare equivalent, then the first element is inserted.

Complexity: Linear in ilist.size().
```
static_flat_set(const static_flat_set& other);
```
Effects: Copy constructor. Constructs the container with the copy of the contents of other.

Complexity: Linear in other.size().
```
static_flat_set(static_flat_set&& other);
```
Effects: Move constructor. Constructs the container with the contents of other using move semantics.

other is not guaranteed to be empty after the move.

other is in a valid but unspecified state after the move.

Complexity: Linear in size.

template <typename Range>
static_flat_set(sfl::from_range_t, Range&& range);

```
template <typename Range>
static_flat_set(sfl::from_range_t, Range&& range, const Compare& comp);
```
Effects: Constructs the container with the contents of range.

If multiple elements in the range have keys that compare equivalent, then the first element is inserted.

Note: It is available in C++11. In C++20 are used proper C++20 range concepts.

(destructor)

```
~static_flat_set();
```
Effects: Destructs the container. The destructors of the elements are called and the used storage is deallocated.

Complexity: Linear in size.

operator=

```
static_flat_set& operator=(const static_flat_set& other);
```
Effects: Copy assignment operator. Replaces the contents with a copy of the contents of other.

Returns: *this().

Complexity: Linear in size.
```
static_flat_set& operator=(static_flat_set&& other);
```
Effects: Move assignment operator. Replaces the contents with those of other using move semantics.

other is not guaranteed to be empty after the move.

other is in a valid but unspecified state after the move.

Returns: *this().

Complexity: Linear in size.
```
static_flat_set& operator=(std::initializer_list<Key> ilist);
```
Preconditions: ilist.size() <= capacity()

Effects: Replaces the contents with those identified by initializer list ilist.

Returns: *this().

Complexity: Linear in size.

key_comp

```
key_compare key_comp() const;
```
Effects: Returns the function object that compares the keys, which is a copy of this container's constructor argument comp.

Complexity: Constant.

value_comp

```
value_compare value_comp() const;
```
Effects: Returns a function object that compares objects of type value_type.

Complexity: Constant.

begin, cbegin

```
iterator begin() noexcept;
```
```
const_iterator begin() const noexcept;
```
```
const_iterator cbegin() const noexcept;
```
Effects: Returns an iterator to the first element of the container. If the container is empty, the returned iterator will be equal to end().

Complexity: Constant.

end, cend

```
iterator end() noexcept;
```
```
const_iterator end() const noexcept;
```
```
const_iterator cend() const noexcept;
```
Effects: Returns an iterator to the element following the last element of the container. This element acts as a placeholder; attempting to access it results in undefined behavior.

Complexity: Constant.

rbegin, crbegin

```
reverse_iterator rbegin() noexcept;
```

const_reverse_iterator rbegin() const noexcept;

```
const_reverse_iterator crbegin() const noexcept;
```
Effects: Returns a reverse iterator to the first element of the reversed container. It corresponds to the last element of the non-reversed container. If the container is empty, the returned iterator is equal to rend().

Complexity: Constant.

rend, crend

```
reverse_iterator rend() noexcept;
```

const_reverse_iterator rend() const noexcept;

```
const_reverse_iterator crend() const noexcept;
```
Effects: Returns a reverse iterator to the element following the last element of the reversed container. It corresponds to the element preceding the first element of the non-reversed container. This element acts as a placeholder, attempting to access it results in undefined behavior.

Complexity: Constant.

nth

```
iterator nth(size_type pos) noexcept;
```
```
const_iterator nth(size_type pos) const noexcept;
```
Preconditions: pos <= size()

Effects: Returns an iterator to the element at position pos.

If pos == size(), the returned iterator is equal to end().

Complexity: Constant.

index_of

```
size_type index_of(const_iterator pos) const noexcept;
```
Preconditions: cbegin() <= pos && pos <= cend()

Effects: Returns position of the element pointed by iterator pos, i.e. std::distance(begin(), pos).

If pos == end(), the returned value is equal to size().

Complexity: Constant.

empty

```
bool empty() const noexcept;
```
Effects: Returns true if the container has no elements, i.e. whether begin() == end().

Complexity: Constant.

full

```
bool full() const noexcept;
```
Effects: Returns true if the container is full, i.e. whether size() == capacity().

Complexity: Constant.

size

```
size_type size() const noexcept;
```
Effects: Returns the number of elements in the container, i.e. std::distance(begin(), end()).

Complexity: Constant.

max_size

```
static constexpr size_type max_size() const noexcept;
```
Effects: Returns the maximum number of elements the container is able to hold, i.e. N.

Complexity: Constant.

capacity

```
static constexpr size_type capacity() const noexcept;
```
Effects: Returns the maximum number of elements the container is able to hold, i.e. N.

Complexity: Constant.

available

```
size_type available() const noexcept;
```
Effects: Returns the number of elements that can be inserted into the container, i.e. capacity() - size().

Complexity: Constant.

clear

```
void clear() noexcept;
```
Effects: Erases all elements from the container. After this call, size() returns zero and capacity() remains unchanged.

Complexity: Linear in size().

emplace

```
template <typename... Args>
std::pair<iterator, bool> emplace(Args&&... args);
```
Preconditions: !full()

Effects: Inserts new element into the container if the container doesn't already contain an element with an equivalent key.

New element is constructed as value_type(std::forward<Args>(args)...).

The element may be constructed even if there already is an element with the key in the container, in which case the newly constructed element will be destroyed immediately.

Returns: The iterator component points to the inserted element or to the already existing element. The bool component is true if insertion happened and false if it did not.

emplace_hint

```
template <typename... Args>
iterator emplace_hint(const_iterator hint, Args&&... args);
```
Preconditions:
1. !full()
2. cbegin() <= hint && hint <= cend()
Effects: Inserts new element into the container if the container doesn't already contain an element with an equivalent key.

New element is constructed as value_type(std::forward<Args>(args)...).

The element may be constructed even if there already is an element with the key in the container, in which case the newly constructed element will be destroyed immediately.

Iterator hint is used as a suggestion where to start to search insert position.

Returns: Iterator to the inserted element or to the already existing element.

insert

```
std::pair<iterator, bool> insert(const value_type& value);
```
Preconditions: !full()

Effects: Inserts copy of value if the container doesn't already contain an element with an equivalent key.

Returns: The iterator component points to the inserted element or to the already existing element. The bool component is true if insertion happened and false if it did not.
```
std::pair<iterator, bool> insert(value_type&& value);
```
Preconditions: !full()

Effects: Inserts value using move semantics if the container doesn't already contain an element with an equivalent key.

Returns: The iterator component points to the inserted element or to the already existing element. The bool component is true if insertion happened and false if it did not.
```
template <typename K>
std::pair<iterator, bool> insert(K&& x);
```
Preconditions: !full()

Effects: Inserts new element if the container doesn't already contain an element with a key equivalent to x.

New element is constructed as value_type(std::forward<K>(x)).

Note: This overload participates in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling this function without constructing an instance of Key.

Returns: The iterator component points to the inserted element or to the already existing element. The bool component is true if insertion happened and false if it did not.
```
iterator insert(const_iterator hint, const value_type& value);
```
Preconditions:
1. !full()
2. cbegin() <= hint && hint <= cend()
Effects: Inserts copy of value if the container doesn't already contain an element with an equivalent key.

Iterator hint is used as a suggestion where to start to search insert position.

Returns: Iterator to the inserted element or to the already existing element.
```
iterator insert(const_iterator hint, value_type&& value);
```
Preconditions:
1. !full()
2. cbegin() <= hint && hint <= cend()
Effects: Inserts value using move semantics if the container doesn't already contain an element with an equivalent key.

Iterator hint is used as a suggestion where to start to search insert position.

Returns: Iterator to the inserted element or to the already existing element.
```
template <typename K>
iterator insert(const_iterator hint, K&& x);
```
Preconditions:
1. !full()
2. cbegin() <= hint && hint <= cend()
Effects: Inserts new element if the container doesn't already contain an element with a key equivalent to x.

New element is constructed as value_type(std::forward<K>(x)).

Iterator hint is used as a suggestion where to start to search insert position.

Note: This overload participates in overload resolution only if all following conditions are satisfied:
1. Compare::is_transparent exists and is a valid type. It allows calling this function without constructing an instance of Key.
2. std::is_convertible_v<K&&, iterator> is false.
3. std::is_convertible_v<K&&, const_iterator> is false.
Returns: Iterator to the inserted element or to the already existing element.
```
template <typename InputIt>
void insert(InputIt first, InputIt last);
```
Preconditions: std::distance(first, last) <= available()

Effects: Inserts elements from range [first, last) if the container doesn't already contain an element with an equivalent key.

If multiple elements in the range have keys that compare equivalent, then the first element is inserted.

The call to this function is equivalent to:
```
while (first != last)
{
    insert(*first);
    ++first;
}
```
Note: This overload participates in overload resolution only if InputIt satisfies requirements of LegacyInputIterator.
```
void insert(std::initializer_list<value_type> ilist);
```
Preconditions: ilist.size() <= available()

Effects: Inserts elements from initializer list ilist if the container doesn't already contain an element with an equivalent key.

If multiple elements in the range have keys that compare equivalent, then the first element is inserted.

The call to this function is equivalent to insert(ilist.begin(), ilist.end()).

insert_range

```
template <typename Range>
void insert_range(Range&& range);
```
Effects: Inserts elements from range if the container doesn't already contain an element with an equivalent key.

If multiple elements in the range have keys that compare equivalent, then the first element is inserted.

Note: It is available in C++11. In C++20 are used proper C++20 range concepts.

erase

```
iterator erase(iterator pos);
```
```
iterator erase(const_iterator pos);
```
Preconditions: cbegin() <= pos && pos < cend()

Effects: Removes the element at pos.

Returns: Iterator following the last removed element.
```
iterator erase(const_iterator first, const_iterator last);
```
Preconditions: cbegin() <= first && first <= last && last <= cend()

Effects: Removes the elements in the range [first, last).

Returns: Iterator following the last removed element.
```
size_type erase(const Key& key);
```
```
template <typename K>
size_type erase(K&& x);
```
Effects: Removes the element (if one exists) with the key equivalent to key or x.

Note: Overload (5) participates in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling this function without constructing an instance of Key.

Returns: Number of elements removed (0 or 1).

swap

```
void swap(static_flat_set& other);
```
Effects: Exchanges the contents of the container with those of other.

Complexity: Linear in size.

lower_bound

```
iterator lower_bound(const Key& key);
```

const_iterator lower_bound(const Key& key) const;

template <typename K>
iterator lower_bound(const K& x);

```
template <typename K>
const_iterator lower_bound(const K& x) const;
```
Effects: Returns an iterator pointing to the first element with key that compares not less than key or x. Returns end() if no such element is found.

Note: Overloads (3) and (4) participate in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling these functions without constructing an instance of Key.

Complexity: Logarithmic in size().

upper_bound

```
iterator upper_bound(const Key& key);
```

const_iterator upper_bound(const Key& key) const;

template <typename K>
iterator upper_bound(const K& x);

```
template <typename K>
const_iterator upper_bound(const K& x) const;
```
Effects: Returns an iterator pointing to the first element with key that compares greater than key or x. Returns end() if no such element is found.

Note: Overloads (3) and (4) participate in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling these functions without constructing an instance of Key.

Complexity: Logarithmic in size().

equal_range

std::pair<iterator, iterator> equal_range(const Key& key);

std::pair<const_iterator, const_iterator> equal_range(const Key& key) const;

template <typename K>
std::pair<iterator, iterator> equal_range(const K& x);

```
template <typename K>
std::pair<const_iterator, const_iterator> equal_range(const K& x) const;
```
Effects: Returns a range containing all elements with key that compares equivalent to key or x.
- The first iterator in pair points to the first element that compares not less than key or x. It is equal to end() if no such element is found.
- The second iterator in pair points to the first element that compares greater than key or x. It is equal to end() is no such element is found.
Note: Overloads (3) and (4) participate in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling these functions without constructing an instance of Key.

Complexity: Logarithmic in size().

find

```
iterator find(const Key& key);
```

const_iterator find(const Key& key) const;

template <typename K>
iterator find(const K& x);

```
template <typename K>
const_iterator find(const K& x) const;
```
Effects: Returns an iterator pointing to the element with key equivalent to key or x. Returns end() if no such element is found.

Note: Overloads (3) and (4) participate in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling these functions without constructing an instance of Key.

Complexity: Logarithmic in size().

count

```
size_type count(const Key& key) const;
```
```
template <typename K>
size_type count(const K& x) const;
```
Effects: Returns the number of elements with key equivalent to key or x, which is either 1 or 0 since this container does not allow duplicates.

Note: Overload (2) participates in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling this function without constructing an instance of Key.

Complexity: Logarithmic in size().

contains

```
bool contains(const Key& key) const;
```
```
template <typename K>
bool contains(const K& x) const;
```
Effects: Returns true if the container contains an element with key equivalent to key or x, otherwise returns false.

Note: Overload (2) participates in overload resolution only if Compare::is_transparent exists and is a valid type. It allows calling this function without constructing an instance of Key.

Complexity: Logarithmic in size().

data

```
value_type* data() noexcept;
```
```
const value_type* data() const noexcept;
```
Effects: Returns pointer to the underlying array serving as element storage. The pointer is such that range [data(), data() + size()) is always a valid range, even if the container is empty. data() is not dereferenceable if the container is empty.

Complexity: Constant.

Non-member Functions

operator==

```
template <typename K, std::size_t N, typename C>
bool operator==
(
    const static_flat_set<K, N, C>& x,
    const static_flat_set<K, N, C>& y
);
```
Effects: Checks if the contents of x and y are equal.

The contents of x and y are equal if the following conditions hold:
- x.size() == y.size()
- Each element in x compares equal with the element in y at the same position.
The comparison is performed by std::equal. This comparison ignores the container's ordering Compare.

Returns: Returns true if the contents of the x and y are equal, false otherwise.

operator!=

```
template <typename K, std::size_t N, typename C>
bool operator!=
(
    const static_flat_set<K, N, C>& x,
    const static_flat_set<K, N, C>& y
);
```
Effects: Checks if the contents of x and y are equal.

For details see operator==.

Returns: Returns true if the contents of the x and y are not equal, false otherwise.

operator<

```
template <typename K, std::size_t N, typename C>
bool operator<
(
    const static_flat_set<K, N, C>& x,
    const static_flat_set<K, N, C>& y
);
```
Effects: Compares the contents of x and y lexicographically. The comparison is performed by a function std::lexicographical_compare. This comparison ignores the container's ordering Compare.

Returns: true if the contents of the x are lexicographically less than the contents of y, false otherwise.

operator>

```
template <typename K, std::size_t N, typename C>
bool operator>
(
    const static_flat_set<K, N, C>& x,
    const static_flat_set<K, N, C>& y
);
```
Effects: Compares the contents of lhs and rhs lexicographically.

The comparison is performed by a function std::lexicographical_compare. This comparison ignores the container's ordering Compare.

Returns: true if the contents of the x are lexicographically greater than the contents of y, false otherwise.

operator<=

```
template <typename K, std::size_t N, typename C>
bool operator<=
(
    const static_flat_set<K, N, C>& x,
    const static_flat_set<K, N, C>& y
);
```
Effects: Compares the contents of x and y lexicographically. The comparison is performed by a function std::lexicographical_compare. This comparison ignores the container's ordering Compare.

Returns: true if the contents of the x are lexicographically less than or equal to the contents of y, false otherwise.

operator>=

```
template <typename K, std::size_t N, typename C>
bool operator>=
(
    const static_flat_set<K, N, C>& x,
    const static_flat_set<K, N, C>& y
);
```
Effects: Compares the contents of x and y lexicographically. The comparison is performed by a function std::lexicographical_compare. This comparison ignores the container's ordering Compare.

Returns: true if the contents of the x are lexicographically greater than or equal to the contents of y, false otherwise.

swap

template <typename K, std::size_t N, typename C>
void swap
(
    static_flat_set<K, N, C>& x,
    static_flat_set<K, N, C>& y
);

Effects: Swaps the contents of x and y. Calls x.swap(y).

erase_if

```
template <typename K, std::size_t N, typename C, typename Predicate>
typename static_flat_set<K, N, C>::size_type
    erase_if(static_flat_set<K, N, C>& c, Predicate pred);
```
Effects: Erases all elements that satisfy the predicate pred from the container.

pred is unary predicate which returns true if the element should be removed.

Returns: The number of erased elements.

Complexity: Linear.

End of document.

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sfl::static_flat_set

Summary

Template Parameters

Public Member Types

Public Data Members

static_capacity

Public Member Functions

(constructor)

(destructor)

operator=

key_comp

value_comp

begin, cbegin

end, cend

rbegin, crbegin

rend, crend

nth

index_of

empty

full

size

max_size

capacity

available

clear

emplace

emplace_hint

insert

insert_range

erase

swap

lower_bound

upper_bound

equal_range

find

count

contains

data

Non-member Functions

operator==

operator!=

operator<

operator>

operator<=

operator>=

swap

erase_if